Fluid pressure device

ABSTRACT

A rotary motor includes a casing in which there is disposed a shaft mounted on an externally toothed gear. The shaft can rotate about its axis without orbital or planetating movement by the aid of an outer cylinder and cams provided in the interspace between the gear and outer cylinder and contacting them when the pressure fluid is introduced in the interspace to move the cams, cylinder and gear.

United States Patent [191 Takagi Dec. 11, 1973 FLUID PRESSURE DEVICE [76] Inventor: M 'ukiTakagi,3l,Katayama,

N" '-shi, Japan [22] Filed: May 18, 1972 [21] Appl. No.: 254,639

[30] Foreign Application Priority Data May 22, 1971 Japan 46/34873 [52] U. /6l, 418/160 [51] In. F04 6,F01c [58] Field of Search 418/61,

[56] References Cited UNITED STATES PATENTS 1,935,096 11/1933 Muller ..418/61X 2,423,507 7/1947 Lawton 418/61 Primary Examiner-Al Lawr Assistant Exami -Robert ner Attorney Karl L. Spivak Smith arrett [57] ABSTRACT A ro motor includes a casing in which there is disshaft mounted on an exter toothed g nally shaft can rotate about it is without orbita the l of an outer cylinder interspace between the gear and outer der and contacting them when the pressure fluid is introduced in the interspace to move ylinder and the cams, c

planetating moveme and earns p ed i gear.

4 laims Qrewinefieeee FLUID PRESSURE DEVICE BACKGROUND OF THE INVENTION This invention relates to fluid pressure devices and more particularly to those used with, for example, rotary pumps and motors.

A fluid pressure device known to date comprises a fixed internally toothed member and movable externally toothed member. To the latter member is fixed a.

shaftwhich is rotated. by introducing pressure oil into the annularinterspace between both toothed members through oil conducting means. With such device, the shaft of the externally toothed member makes not only a rotation about its axis but also a revolution or orbital movement. To attain only the rotation of said shaft without its orbitalor planetary movement, the prior art fluid pressure deviceis necessarily provided with a separate shaft fitted. to one end of the first mentioned shaft,for example, through a universal point, resulting in considerable loss of required energy and complicated arrangement.

SUMMARY OF INVENTION It-is accordingly the object of this invention to provide a fluid pressure device capable of providing a large torque. A fluid pressure device according to this invention has an externally toothed member fitted with a shaft, which is so designed as to make a rotation about itsaxis without orbital movement, eliminating the necessity of using, for example, a universal joint as required for the prior art device which is intended to effect only the rotation of the shaft without its orbital or planetary movement. Accordingly, the present fluid pressuredevice provides a relatively large torque and also is of simple construction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional view of a fluid pressure device according to this invention;

FIG. 2 is a sectional view on line 2-2 of FIG. 1;

FIG. 3A schematically shows the arrangement of seven fluid holes formed in a connection plate; and

1 FIG. 3B schematically indicates the arrangements of first and second groups each of six fluid holes bored in a sleeve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS There will now =be described by reference to FIG. 1 a fluid pressure device according to an embodiment of this invention applied in a rotary motor. Referring to FIG. 1, numeral denotes a cylindrical casing. Along the axis there are formed alarge diameter space 11 and a small diameter space 12. In the inside of the peripheral wall of the small'diameter space 12 are cut annular grooves 13 and 14 arranged at a prescribed space in the axial direction. Saidperipheral wall is also bored with an inlet port 15 and an outlet port 16 so as to communicate with the annular grooves 13 and 14. Along the central axis of the casing 10 is pivotally supported a rotatable shaft 17 by bearings 18. The casing 10 is closed at one open end with a cap member 19 and at the other open end with another cap member 20 bored with a through hole enabling-one end of the shaft 17 to extend therethrough tothe*outside. To the rotatable shaft 17 is fitted a gear 21 disposed in the large diameter space i 11 of the casing 10 by engagement with the spline secand gear 21.

tion 17a of the rotatable shaft 17. The gear 21 has a plurality of, for example, six external teeth 21a of which tooth surface and the bottom land between the adjacent teeth define a gently curved outline.

In the large diameter space 11 of the casing 10 is disposed an outer cylindrical member 22 whose inner wall spatially faces the external teeth of said gear 21. The

cylindrical member 22 is made rotatable in a direction perpendicular to the shaft 17 in a space allowed therefor so as to cause its center 0 to be displaced from the center 0 of the rotatable shaft 17 or gear 21 so as to planetate about the center 0. Between the cylindrical member 22 and the gear 2lreceived therein are provided seven pins 23 and seven cylindrical cam rollers 24. Those rollers 24 are equidistantly arranged on the same periphery, and their outer peripheral surfacealways abuts against the inner wall of arcuate grooves 22a cut in the inner peripheral wall of the cylindrical member 22 and the external teeth of the gear 21. Each pin 23 loosely penetrates a roller 24 with part of the outer surface of the pin 23 pressed on part of the inner peripheral wall of the roller 24, and is fixed at one end to the casing 10 and at the other to the later described connection plate. The orbital movement of the cylindrical member 22 causes each roller 24 eccentrically to turn about a pin 23 with the resultant rotation of. the gear 21.

In the large diameter space 11 of the casing 10 is disposed a connection plate or disk 25 concentrically with the shaft 17. One side of theconnection disk 25 abuts against one side of the cylindrical member 22, rollers 24 and gear 21 respectively, and the other side of the connection disk 25 contacts the vertical inner wall of the casing 10. To the connection disk 25 is connected, as previously described, one end of each pin 23, the otherend of which is fixed to the casing 10. Thus it will be seen that the connection disk 25 is indirectly fixed to the casing 10. The connection disk 25 is bored with seven fluid holes, that is, the same number as that of the rollers 24, which. are equidistantly arranged on the same periphery, one end of said holes 26 being open to the space defined between the cylindrical member 22 In the smaller "diameter space of the casing 10 is disposed a sleeve 27 whose inner peripheral wall engages the spline section 17a of the shaft 17 so as to rotate jointly therewith. The outer peripheral wall of the sleeve 27 slidably abuts against the inner wall of the casing 10. Accordingly, the open side of the annular grooves 13 and 14 cut in said inner wall is closed with the sleeve 27. The sleeve 27 is bored with first and second groups, each of six fluid holes 28 and 29. The fluid holes 28 of the first group are equidistantly arranged on the same periphery, oneend of said holes being open to the annular groove 13 and the other end being open to that end face of said sleeve 27 which slidably abuts against the connection disk 25.

When, therefore, the sleeve 27 makes a prescribed rotation, the annular groove 13 is aligned with thefluid hole 26 of the connection disk 25. The fluid holes 29 of the second group are equidistantly positioned on the same periphery such that each of them is interposed between two adjacent fluid holes 28. The fluid holes 29 of the second group are open at one end to the annular groove 14 and at the other end open to the end face of the sleeve 27. When, therefore, the sleeve 27 makes a prescribed rotation, the annular groove 14 communicates with the fluid hole 26 of the connection disk 25. Accordingly, the rotation of the shaft 17 and in consequence the sleeve 27 causes pressure fluid to be supplied to the interspace between the gear 21 and cylindrical member 22 through the inlet port 15, annular groove 13 and fluid holes 28 and 26 in turn. The pressure fluid reaching said interspace is discharged through the fluid holes 26 and 29, annular groove 14 andoutlet port 16 in turn.

There will now be described the operation of a rotary motor constructed as described above. The pressure fluid introduced through the inlet port is brought through some of the fluid holes 26 communicating with some'of the fluid holes of the first group 28 to the corresponding section of the annular interspace between the gear 21 and cylindrical member 22. The fluid pressure is applied to that part of the inner periphery of the cylindrical member 22, the roller 24 and the external teeth of the gear 21 in such proportions a to cause the gear 21 to produce a clockwise torque: As the result, the gear 21 makes a partial clockwise rotation jointly with the rotatable shaft 17 to an extent equal to a fraction of one full rotation divided by the six teeth of the gear 21, that is, through a peripheral angle of 60. At this time, the rollers 24 pressed against the gear 21 rotates counterclockwise through the same angle as the gear 21. The rotation of the roller is carried out by sliding on the inner wall of the arcuate groove 22a of the cylindrical member 22, which consequently makes a counterclockwise orbital movement while being supported by the rollers 24. In other words, the cylindrical member 22 plan'etates eccentrically about the central axial line 0 of the gear 21 as the result of its rotation. At this time, part of the pressure fluid supplied to the interspace between the gear 21 and cylindrical member 22 is drawn out through a fluid hole 26 and outlet port 16 in turn. The partial rotation of the shaft 17 causes another fluid hole 26 to communicate with another hole of the first group 28, carrying out the same operation asdescribed above. Repetition of said operation eventually leads to the continuous rotation of the shaft 17.

With a rotary motor of the aforementioned construction, the cylindrical member 22 itself surrounding the gear 21 revolves, enabling the gear 21 and shaft 17 to make a rotation without orbital movement. Therefore, the rotating force of the shaft 17 can be directly drawn out without the aid of, for example, a universal joint required for the prior art fluid pressure device. Accordingly, when applied to a rotary motor, the fluid pressure devide of this invention provides a large torque, and when used with a rotary pump, realizes the very efficient rotation of the gear.

it will be apparent that with the fluid pressure device I of this invention, the gear for rotation the shaft is not limited to a type of the aforesaid construction, but may have its teeth freely varied in number and shape.

Further, the roller so disposed asto slidably abut against the gear and cylindrical member need not be limited to a cylindrical shape, but may take any other form, for example, an eccentric cam, provided it permits the eccentric revolution of the cylindrical member. Moreover, the number of rollers and fluid holes is open to free choice.

What I claim is:

1. A fluid pressure device comprising A. a casing;

B. a rotary shaft rotatably supported in the casing,

1. said shaft having a center and having rotary movement about the center;

C. a gear mounted coaxially with the rotary shaft and having external teeth;

D. a movable cylindrical member having an inner side,

1. said cylindrical member being located eccentrically with the gear to form an annular interspace between the inner side of the cylindrical member and the external teeth of the gear;

E. conducting means for introducing the fluid pressure into the annular interspace and discharging it therefrom with the pressure so distributed as to move the gear and the cylindrical member;

F. cam means provided in the annular interspace and having a cam periphery,

1. said cam periphery contacting the teeth of the gear and the inner side of the cylindrical member,

2. the cam means planetating the cylindrical member about the said center and rotating the gear about the center by introducing the fluid pressure into the annular interspace and discharging it therefrom,

3. the cam means comprising a plurality of rollers having outer sides and inner sides,

a. the outer sides of the rollers being contacted by the teeth of the gear and the inner side of the cylindrical member, and

4. a plurality of pins fixed to the casing and having outer sides,

a. each pin being loosely inserted into a corresponding roller with the outer side contacting a part of the inner side of the roller, whereby the rotary shaft continuously rotates without orbital movement.

2. A fluid pressure device accordingv to claim 1 wherein the teeth of the gear have a curbed tooth surface.

3. A fluid pressure device according to claim 1 wherein the conducting means comprises first fluid passing means formed in a connecting plate fixed to the casing, second and third fluid passing means formed in a sleeve mounted coaxially with the rotary shaft, and an inlet hole and outlet hole perforated in the wall of the casing, the second and third fluid passing means conducting the first fluid passing means to the inlet and outlet holes so that the pressure fluid is introduced into the annular interspace through the inlet hole, second fluid passing means and the part of the first fluid passing means and the pressure fluid in the annular interspace is discharged through the part of the first fluid passing means and third fluid passing means and the outlet hole.

4. A fluid pressure device according to claim 3 wherein the first fluid passing means consists of the same-number of first holes as that of the rollers, one end of the first hole opening to the annular interspace and the other end opening to the side of the sleeve, second fluid passing means consists of a smaller number of second holes than that of the first holes, one end of the second hole opening to the side of the connecting plate and the other end opening to the inlet hole, and the third fluid passing means consists of the same number of third holes as the second holes, one end of the third hole opening to the side of the connecting plate and the other opening to the outlet hole. 

1. A fluid pressure device comprising A. a casing; B. a rotary shaft rotatably supported in the casing,
 1. said shaft having a center and having rotary movement about the center; C. a gear mounted coaxially with the rotary shaft and having external teeth; D. a movable cylindrical member having an inner side,
 1. said cylindrical member being located eccentrically with the gear to form an annular interspace between the inner side of the cylindrical member and the external teeth of the gear; E. conducting means for introducing the fluid pressure into the annular interspace and discharging it therefrom with the pressure so distributed as to move the gear and the cylindrical member; F. cam means provided in the annular interspace and having a cam periphery,
 1. said cam periphery contacting the teeth of the gear and the inner side of the cylindrical member,
 2. the cam means planetating the cylindrical member about the said center and rotating the gear about the center by introducing the fluid pressure into the annular intErspace and discharging it therefrom,
 3. the cam means comprising a plurality of rollers having outer sides and inner sides, a. the outer sides of the rollers being contacted by the teeth of the gear and the inner side of the cylindrical member, and
 4. a plurality of pins fixed to the casing and having outer sides, a. each pin being loosely inserted into a corresponding roller with the outer side contacting a part of the inner side of the roller, whereby the rotary shaft continuously rotates without orbital movement.
 2. the cam means planetating the cylindrical member about the said center and rotating the gear about the center by introducing the fluid pressure into the annular intErspace and discharging it therefrom,
 2. A fluid pressure device according to claim 1 wherein the teeth of the gear have a curbed tooth surface.
 3. A fluid pressure device according to claim 1 wherein the conducting means comprises first fluid passing means formed in a connecting plate fixed to the casing, second and third fluid passing means formed in a sleeve mounted coaxially with the rotary shaft, and an inlet hole and outlet hole perforated in the wall of the casing, the second and third fluid passing means conducting the first fluid passing means to the inlet and outlet holes so that the pressure fluid is introduced into the annular interspace through the inlet hole, second fluid passing means and the part of the first fluid passing means and the pressure fluid in the annular interspace is discharged through the part of the first fluid passing means and third fluid passing means and the outlet hole.
 3. the cam means comprising a plurality of rollers having outer sides and inner sides, a. the outer sides of the rollers being contacted by the teeth of the gear and the inner side of the cylindrical member, and
 4. a plurality of pins fixed to the casing and having outer sides, a. each pin being loosely inserted into a corresponding roller with the outer side contacting a part of the inner side of the roller, whereby the rotary shaft continuously rotates without orbital movement.
 4. A fluid pressure device according to claim 3 wherein the first fluid passing means consists of the same number of first holes as that of the rollers, one end of the first hole opening to the annular interspace and the other end opening to the side of the sleeve, second fluid passing means consists of a smaller number of second holes than that of the first holes, one end of the second hole opening to the side of the connecting plate and the other end opening to the inlet hole, and the third fluid passing means consists of the same number of third holes as the second holes, one end of the third hole opening to the side of the connecting plate and the other opening to the outlet hole. 